The Milk Producer - June 2011 - (Page 28)

RESEARCH By Natalie Osborne Value-added protection Extending the life of milk-producing cells in udders could yield a healthful product for people P rotecting milk-producing cells in the laboratory, and treated them in a cow’s mammary tissue with levels of selenium similar to concould improve and prolong centrations in a selenium-enriched milk production. What’s more, prodiet. Selenium increased cell survival tecting these cells—called bovine by reducing the expression of a spemammary epithelial cells—could procific protein that activates cell death vide a value-added dairy product that through mitochondria. reduces human cancer risk. Now, they’re examining whether A process called oxidative stress selenium has the same effect on living often causes mammary epithelial cell animals. PhD student Scott Cieslar death in dairy cows, explains the Unifed organic-selenium-enriched diets versity of Guelph’s Dr. Silvio Miranto 80 cows at the Elora Dairy Reda, department of animal and poultry search Station, and took samples of science. This stress results in oxygen’s their mammary tissue. Now, he’s anareactive and unstable byproducts lysing the mammary cells to see if the triggering the cells’ natural, built-in selenium affected their survival and self-destruct mechanism. However, anti-oxidant status. a mineral commonly supplemented “If you can decrease cell death or in dairy rations—selenium—can prevent this programmed cell death by reducing the oxidative stress, he has found. “Certain factors, such as highfat diets, can increase oxidative stress because fat requires more metabolism and releases more reactive oxygen byproducts,” says Miranda. “When a cow is under oxidative stress during lactation, cells from her mammary glands will die and milk yield will drop.” Miranda and his team wondered exactly how oxygen byproducts activated the cell-death mechanism. Most of the activation comes from mitochondria— energy-producing cellular components. Mammary epithelial cells contain an abundance of mitochondria for producing the energy needed to make milk. Selenium-enriched milk could potentially Researchers induced oxidative help fight cancer in humans. stress in mammary epithelial cells 28 | June 2011 | MilkPRODUCER increase cell growth, you’ll get a more persistent lactation,” says Cieslar. “In fact, our preliminary results indicate the cells from selenium-treated cows had lower levels of the signalling protein responsible for triggering cell death.” Another project goal is to produce selenium-enriched milk with anticarcinogenic activity in humans. Selenium fed to cows is readily available in their milk, and could boost anti-oxidative capacity in people who consume it. Researchers plan to isolate the selenium protein from this enriched milk, feed it to rodents with cancer or diabetes and examine its ability to reduce or slow progression of these diseases. “Right now, many people in the industry focus on increasing traits such as milk yield, reproduction and immune function. Now we have to pay attention to the final product—after all, we are the final consumers,” says Miranda. “Canada is making a big effort to improve the quality of animal products like milk, and one way to do this is with selenium.” Natalie Osborne is a student writer with the University of Guelph’s office of research. Collaborators include Profs. John Cant, Brenda Coomber and Vern Osborne. Funding for this research is provided by Dairy Farmers of Ontario, Natural Sciences and Engineering Research Council, Ontario Ministry of Agriculture, Food and Rural Affairs and Alltech.

Table of Contents for the Digital Edition of The Milk Producer - June 2011

The Milk Producer - June 2011
Contents
Editor’s Notes
DFO Chair’s Message
Dairy Update
Industry Roundup
DFC Promotion
Research
Applied Science
Ruminations
Rearing Replacements
Markets
New ’N’ Noted
Back Forty

The Milk Producer - June 2011